• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.40-46
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• 2013

A variety of nuruk were collected from various provinces in Korea, and their microflora profiles were analyzed at the species level. A total of 42 nuruk samples were collected and when the viable cell numbers in these nuruk were enumerated, the average cell numbers of bacteria, fungi, yeast, and lactic acid bacteria from all nuruk were 7.21, 7.91, 3.49, and 4.88 log CFU/10 g, respectively. There were no significant differences in viable cell numbers of bacteria or fungi according to regions collected. Bacillus amyloliquefaciens and B. subtilis were the predominant bacterial strains in most samples. A significant portion, 13 out of 42 nuruk, contained foodborne pathogens such as B. cereus or Cronobacter sakazakii. There were various species of lactic acid bacteria such as Enterococcus faecium and Pediococcus pentosaceus in nuruk. It was unexpectedly found that only 13 among the 42 nuruk samples contained Aspergillus oryzae, the representative saccharifying fungi in makgeolli, whereas a fungi Lichtheimia corymbifera was widely distributed in nuruk. It was also found that Pichia jadinii was the predominant yeast strain in most nuruk, but the representative alcohol fermentation strain, Saccharomyces cerevisiae, was isolated from only 18 out of the 42 nuruk. These results suggested that a variety of species of fungi and yeast were distributed in nuruk and involved in the fermentation of makgeolli. In this study, a total of 64 bacterial species, 39 fugal species, and 15 yeast species were identified from nuruk. Among these strains, 37 bacterial species, 20 fungal species, and 8 yeast species were distributed less than 0.1%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.6
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• pp.928-934
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• 2015

The objective of this study was to reduce Nuruk flavor in Korean rice-distilled liquor using different ratios of $Sumizyme^{TM}$ and Nuruk. After 9 days of fermentation at $28^{\circ}C$, alcohol contents and pH were 16.0~17.1% and 3.82~4.16, respectively. An increased ratio of $Sumizyme^{TM}$ decreased alcohol content while increased pH of the mash. In alcohol contents, there were no significant differences up to 30% substitution of Nuruk to $Sumizyme^{TM}$. A descriptive analysis was conducted with trained panelists for determining the intensity of Nuruk flavor. The intensities of Nuruk flavor in mashes and distilled liquors brewed by traditional Nuruk, cultured Nuruk, and a mixture of 30% $Sumizyme^{TM}$ and 70% cultured Nuruk were evaluated. The mash and distilled liquor prepared using a mixture of 30% $Sumizyme^{TM}$ and 70% cultured Nuruk showed significantly lower intensities of Nuruk flavor when compared with those of mashes and distilled liquors produced by the traditional and cultured Nuruk.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1461-1466
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• 2013

In this study, we ascertained the characteristics of crude protease extracted from fruits (fig, kiwifruit and pineapple) as well as traditional Korean fermentation starters (bio nuruk, traditional nuruk, meju and rice koji) to determine their suitability for industrial application. Crude protease extracted from traditional Korean fermentation starters was found to have a higher optimum temperature ($70^{\circ}C$) and salt concentration (1~3%) but a lower optimum pH (3~6) value compared to the corresponding values for the protease extracted from fruits. On comparison, the total activities of protease per gram unit follow the order: bio nuruk> rice koji> traditional nuruk> fig> pineapple> meju> kiwifruit. Based on our results, we conclude that protease extracted from traditional Korean fermentation starters has potential for application in food industry, for example, as a meat tenderizer for sausage manufacturing and as a protease for cheese production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.7
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• pp.1002-1008
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• 2012

For the production of Korea traditional cereal wine makgeolli, a rice fermentation starter nuruk was Rhizopus oryaze CCS01 commercial nuruk. The carbohydrate content of rice nuruk was higher, the levels of moisture, ash, crude protein, and crude fat were lower. In particular, the saccharifying activity of rice nuruk was 2.2 times higher than commercial nuruk. pH, alcohol, and viable yeast cells of makgeolli made rice nuruk were higher than those of makgeolli made commercial nuruk. In contrast, the levels of acidity, $^{\circ}Brix$, viable lactic acid bacteria (LAB) cells, and browning of makgeolli made rice nuruk were lower than those of makgeolli made commercial nuruk, the alcohol content of glutinous rice (GUR) makgeolli made rice nuruk higher other samples. These results suggest that rice nuruk R. oryzae CCS01 make new type cereal makgeolli.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.555-562
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• 1997

The characteristics of mash qualities of takju prepared by using different nuruk (Korean-style bran koji) such as Mucor racemosus nuruk, Rhizopus japonicus nuruk, Aspergillus oryzae nuruk, Aspergillus kawachii nuruk and traditional nuruk were investigated during fermentation. At the begining of fermentation, ethanol content was in the range of $2.0{\sim}3.0%$. However, it increased to $8.2{\sim}12.6%$ after 16 days of fermentation. Takju made from Rhizopus japonicus nuruk showed higher ethanol content than treated otherwise. pH of takju made from Rhizopus japonicus nuruk showed higher value the others. Total acids were $0.15{\sim}0.20%$ at the begining of fermentation, and it increased to $0.086{\sim}1.57%$ after 16 days of fermentation. Total sugar were $16.64{\sim}17.62%$ at the begining of fermentation, but decreased to below 7.00% after 16 days of fermentation. Rhizopus japonicus nuruk showed the lowest level of total sugar content. Except ethanol, iso-amyl alcohol and iso-butyl alcohol were major part of minor alcohol in the mash of takju. Higher concentration of iso-amyl alcohol, iso-butyl alcohol and n-propyl alcohol were found in the mash of Rhizopus japonicus nuruk whereas the level of phenylethyl alcohol was high in the mash of traditional nuruk. Fusel oil was $0.002{\sim}0.411\;mg/mL$ during fermentation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.340-347
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• 2019

This study investigated the brewing properties of rice beer made with yeast isolated from traditional whole wheat nuruk. The experimental method was followed by alcohol fermentation and quality analysis for six months after separating the yeast from nuruk. The yeasts isolated from traditional nuruk showed normal fermentation characteristics, like those of commercial yeast, in terms of alcohol production capability, sugar content, and pH reducing power. Especially, the yeast (KCCM 301) isolated from whole wheat nuruk showed higher contents of glycogen and trehalose than that of commercial yeast, and so KCCM 301 yeast has excellent yeast vitality. Meanwhile, the yeast (KCCM 90301) isolated from traditional Nuruk produced significantly higher alcohol and ester contents than that of commercial yeast. This has a positive effect for supplementing the taste and aroma of rice beer. In conclusion, the yeasts isolated from whole wheat nuruk showed the general alcohol fermentation pattern and aroma content of rice beer. These yeasts seem to be effective in strengthening the flavor of rice beer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.535-542
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• 2019

The purpose of this study was to obtain basic data necessary for making a nuruk salt by comparing and analyzing the ingredients of various nuruk salts, and to select a nuruk salt that meets the users' needs. We selected the types of nuruk as the ihwaguk, miinguk, baekguk, and koji to identify the characteristics of the nuruk, and then analyzed the chemical characteristics after manufacturing the nuruk salts under the same conditions of fermentation, such as material ratio and temperature. In the manufacture of nuruk salt, the pH level dropped from 6.2~6.5 before fermentation to 6.1~6.2 three days after fermentation. The Acidity increased from 0.16~0.18 before fermentation to 0.22~0.25 after fermentation and there was no difference between the nuruk. The sugar content has risen since fermentation, and nuruk salt made by koji showed the largest increase in the sugar content. The salinity of the nuruk salt was raised to 37~44 after fermentation from 30~32 before fermentation and indicated largest increase in nuruk salt made by koji. Organic acids of nuruk salt were detected in the order of acetic acid, oxalic acid, malic acid, lactic acid, and citric acid. The oxalic acid of the baekguk salt was found to be 0.77 mg/mL, 2.3 times more of the koji, and the succinic acid was also found to be the highest with 1.19 mg/mL. Malic acid, lactic acid, acetic acid, and citric acid were found to have the highest amount of koji salt at 0.29 mg/mL, 1.48 mg/mL, and 0.12mg/mL, respectively, making it a better taste to be soft than other nuruk salt.

• Textile Coloration and Finishing
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• v.24 no.4
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• pp.260-269
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• 2012

The aim of this study was to develop higher-value added dyeing materials with the fermentation-dyeing -mordanting system using only the natural ingredients by integrating traditional fermentation techniques with traditional dyeing technique. Nuruk, which is used mainly to ferment traditional foods, was used as a fermenting agent to ferment 5 different types of materials. Acidic burnt alum and alkaline calcium hydroxide were used as natural mordants. The dyeability checked after fermentation showed that both cotton and silk mordanted with Gardenia jasminoides did not show notable changes, and 10 days of fermentation was found to be appropriate. Sophora japonica L. performed better on cotton materials mordanted with slaked lime, and alkaline mordants were found to be more effective than acidic ones. With Rheum coreanum, a fermentation period of more than 24 days ($5^{th}$ fermentation) worked best on cotton material, showing a 5 fold increase in the K/S value after the $5^{th}$ slaked lime fermentation than with no fermentation. Rhus javanica L. was found to increase the color fastness to gentle washing and the fastness to light was found to possess 4 means that natural dyed fabric have the highest level of durability, the grade 1 the lowest level of fastness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5150-5158
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• 2014

This study examined the physicochemical characteristics of mashing prepared using different Nuruks (traditional Nuruk, Nuruk added Aspergillus oryzae, Nuruk added Aspergillus kawachii, and Nuruk added Aspergillus oryzae and Aspergillus kawachii), and to obtain the basic data for Korean Cheongju production. The four different mashes were compared for their brewing characteristics and indicated a normal fermentation pattern. The Nuruk made from A. oryzae or A. kawachii showed higher fermentation ability than the other samples tested. In addition, the analyzed results of fermented mashing showed that the Nuruk made from A. oryzae or A. kawachii had a significantly higher aroma profile, such as higher alcohol and ester than the other samples tested, whereas the Nuruk made from a mixture of A. oryzae and A. kawachii had a much higher organic acid content. In conclusion, the Nuruk prepared using A. oryzae or A. kawachii had a positive effect on the complete fermentation and enhanced aroma compounds for Korean Cheongju production.

• The Korean Journal of Mycology
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• v.36 no.1
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• pp.1-8
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• 2008

To investigate the mycoflora of indoor air in a Sogokju, traditional rice wine, factory, fungi were sampled and analyzed from the air of several rooms in the factory using an Anderson air sampler and from two kinds of Nuruk. Twelve fungal species belonging to the genera of Aspergillus, Penicillium, Gibberella, Cladosporium, and Talaromyces were isolated. Species belonging to Aspergillus and Penicillium genera were the major species. Seven different species of Penicillium were isolated from each different room of the factory. The Aspergillus species found from indoor air of the factory was also found from Nuruk. Rhizopus sp. was commonly isolated from Nuruk but not from indoor air of the factory. This is first report of fungi present in indoor air of a traditional rice wine factory in Korea.